The invention relates to an apparatus at a flat card or roller card for grinding a clothing drawn onto a rotating roller. Some grinding devices have a carrying device with at least one grinding element and an advancing device serving to set the grinding element against the clothing, the apparatus comprising a biasing device serving for automatically continuing to push forward the grinding element in a contact-making direction during the grinding procedure, and the carrying device being attached to the flat card or roller card.
When textile fibres are processed, the fibres are oriented and cleaned with the aid of flat cards or roller cards. Those fibre-processing apparatuses comprise at least one roller having a wall in the shape of a circular cylinder and carrying a fibre-processing clothing on its outer wall surface. For fibre processing, the roller is set in rotary motion relative to its cylinder axis. The clothing arranged on the outer wall surface passes through the fibre material and orients it, optionally in co-operation with further processing elements such as, for example, card flats, clearer rollers and the like. Cleaning of the raw material is, furthermore, also achieved by the fibre processing. In order to increase resistance to wear and to improve the quality of the textile fibre material, a so-called all-steel saw-tooth clothing is usually used as the fibre-processing clothing. A clothing of such a kind comprises a saw-tooth wire running on a helical course around the roller having a wall in the shape of a circular cylinder, the saw-teeth of which wire pass through the fibre material. In operation of the above-described wires, considerable wear of the fibre-processing clothing takes place. In addition, contaminants can gather in the region of that clothing. The latter-described problem especially comes to the fore when processing synthetic fibres, in the course of which the fibres can melt and stick to the clothing. Therefore, in order to achieve the desired quality of fibre material, it is necessary for the fibre-processing clothing to undergo processing regularly in order, in the course of that processing, to re-grind the tips of the clothing and/or to remove contaminants from the clothing.
In the case of a known apparatus (EP 1 430 997 A), after mounting of the grinding arrangement on the machine frame of a flat card or roller card, the desired orientation of the grinding arrangement with respect to the clothing to undergo processing is first adjusted with the aid of an adjusting screw. By that means, the contact pressure (biasing device) of the grinding element against the clothing is adjusted. The processing arrangement is then lifted up off the clothing by actuating a pneumatic lifting cylinder, the roller together with the clothing is caused to rotate and the processing arrangement is advanced towards the clothing by again actuating the pneumatic lifting cylinder. It is disadvantageous that the biasing of the grinding arrangement has to be adjusted in an additional preparatory step, for which the grinding element is firstly set against the non-rotating clothing. In addition, for adjustment of the biasing device, additional outlay in terms of apparatus and installation is required. It is furthermore disadvantageous that, in the case of mobile use or replacement of the apparatus, the time-consuming adjustment procedure is additionally required.
It is an aim of the invention to provide an apparatus of the kind described at the beginning that avoids or mitigates the mentioned disadvantages and that especially is simple in terms of construction and installation and makes it possible to shorten the time until service-readiness for advancing the grinding apparatus and for the grinding procedure.